Respiration and cyanogenesis inPseudomonas aeruginosa

The respiratory ability of batch cultures ofPseudomonas aeruginosa strain 9-D2 peaks during midlog phase at 3.8 nmol O₂/min/10⁸ cells. This ability declines in late log phase, just prior to the time the culture begins to produce cyanide. The respiration of this organism is particularly sensitive to cyanide inhibition during midlog-phase growth, but is extremely resistant to this compound in stationary phase. These inhibition patterns are biphasic for each of these situations and indicate several respiratory responses to HCN. Addition of cyanide to midlog-phase cells resulted in the production of a stationary-phase type of cyanide respiration pattern in 2 h. A non-cyanideproducing mutant of this organism produced significantly less of the cyanide-resistant respiration components.